Improved methods of immunisation are needed both to improve current vaccines and to create new ones. At the same, there is a need to minimise or avoid the use of adjuvants, as only a very limited number have been approved for use in humans, and there is a widespread desire to minimise their use in animals in order to reduce animal suffering.
Recent patent applications describe the use of mammalian C4 bp oligomerisation domains to increase the immunogenicity of antigens in mammals. These applications include PCT/IB2004/002717 and PCT/EP03/08926. An earlier patent, WO91/11461, discussed the use of C4 bp protein fusions for immunisation but no successful immunisations were demonstrated. PCT/EP03/08928 describes methods for producing the mammalian C4 bp fusion proteins. However, to date, no C4 bp oligomerisation domain is known for a non-mammalian species. As there is considerable interest in vaccination of non-mammalian species, for example of birds against avian influenza, a C4 bp oligomerisation domain derived from such species would be of considerable utility.
Oshiumi et al. (J. Immunol. 175:724-1734 (2005)) have characterised the regulator of complement activation locus in chicken and identified three proteins which they call CREM, CREG and CRES. Transcripts from each gene were characterised enabling the entire protein sequences to be deduced. One of these proteins, CRES, was described as the chicken C4 bp gene.